Nicotinic acid-modified pyridoxamine polyether polyols and methods for making the same

Abstract

The present application belongs to the technical field of polyether polyols and its preparation, and particularly relates to a nicotinic acid modified pyridoxamine polyether polyol and a preparation method thereof. The preparation method of the nicotinic acid modified pyridoxamine polyether polyol comprises the following steps: pyridoxamine is reacted with an aqueous phosphoric acid solution to be converted into pyridoxamine phosphate; nicotinic acid and the pyridoxamine phosphate are subjected to an esterification reaction under the action of a catalyst of sulfuric acid to obtain nicotinic acid pyridoxamine ester after dehydration; then, the nicotinic acid pyridoxamine ester and a liquid small-molecule alcohol are used as a starter, and are subjected to a polymerization reaction with an alkylene oxide under the action of an alkaline catalyst; and after post-treatment, the nicotinic acid modified pyridoxamine polyether polyol is obtained. The preparation method of the nicotinic acid modified pyridoxamine polyether polyol is simple and environmentally friendly, and does not need to introduce melamine. The nicotinic acid modified pyridoxamine polyether polyol prepared by the preparation method has excellent flame retardant performance, high compressive strength and good pentane solubility.

Description

Technical Field

[0001] This invention belongs to the field of polyether polyols and their preparation technology, specifically relating to a nicotinic acid-modified pyridoxine polyether polyol and its preparation method. Background Technology

[0002] Polyether polyols (polyether for short) are high molecular weight compounds produced by addition polymerization of initiators with ethylene oxide, propylene oxide, etc., under the action of a catalyst. Polyether polyols are characterized by high molecular weight, low viscosity, high activity, and hydrophilicity, making them important raw materials for the manufacture of polyurethane plastics and foams. They are widely used in automotive seats, furniture, building insulation, and other fields. In addition, polyether polyols can also be used as epoxy resin prepolymers, antistatic agents, and lubricants.

[0003] Currently, widely used initiators include sucrose, glycerol, sorbitol, and diethanolamine. The polyether polyols prepared from these initiators have different compound structures and exhibit diverse performance characteristics in rigid polyurethane foams.

[0004] CN112011022A discloses a method for preparing phosphorus-containing flame-retardant polyurethane elastomer. This method involves an addition reaction of phosphate ester with 4-hydroxybutyric acid solution, followed by an esterification reaction with 2-methyl-2,4-pentanediol, and finally uniform mixing with diisocyanate. This method introduces a single phosphorus element, which has a certain flame-retardant effect, but it is somewhat inferior to the flame-retardant effect of a nitrogen-phosphorus synergistic system. Even if nitrogen is introduced during the preparation of the decomposition agent, the process is complex, the preparation cycle is long, and the nitrogen content is low.

[0005] CN117264192A discloses a method for preparing a highly efficient and environmentally friendly flame-retardant polyether polyol. The feature of this process is the use of an amino donor composed of a mixture of melamine and benzomelamine, whose high nitrogen content effectively improves the flame-retardant properties of polyurethane foam. However, the poor solubility of melamine leads to a low yield of the final synthesized polyether polyol.

[0006] Therefore, there is a need to develop a polyether polyol that has simple raw materials, excellent mechanical properties, is easily soluble, and has good flame retardant properties. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the defects of the existing technology and provide a method for preparing nicotinic acid modified pyridoxine polyether polyol. The raw materials are simple and environmentally friendly, and there is no need to introduce melamine. The nicotinic acid modified pyridoxine polyether polyol prepared by the method of the present invention has excellent flame retardant properties, high compressive strength and good pentane solubility.

[0008] The method for preparing nicotinic acid-modified pyridoxine polyether polyol of the present invention involves reacting pyridoxine with an aqueous solution of phosphoric acid to convert it into pyridoxine phosphate. Nicotinic acid and pyridoxine phosphate undergo esterification under the action of sulfuric acid catalyst. After dehydration, nicotinic acid pyridoxine ester is obtained. Subsequently, nicotinic acid pyridoxine ester and liquid small molecule alcohol are used as initiators and polymerized with epoxide alkane under the action of alkaline catalyst. After post-treatment, nicotinic acid-modified pyridoxine phosphate polyether polyol is obtained.

[0009] The specific synthesis process of pyridoxine phosphate is as follows: pyridoxine and 75 wt.% phosphoric acid aqueous solution are added to a reaction vessel at a mass ratio of (1~1.68):1, followed by the addition of solvent, dissolved at room temperature, maintaining a temperature of 105~110℃ and a pressure of -0.08~-0.1 MPa, and dehydrated by vacuum bubbling to obtain pyridoxine phosphate; wherein the solvent is one or both of ethanol and chloroform.

[0010] The specific synthesis process of the nicotinic acid pyridoxine ester is as follows: nicotinic acid and pyridoxine phosphate are added to a reaction vessel in a molar ratio of (1~1.8):1, and then 97wt.% sulfuric acid is added. The esterification reaction is carried out at 200~220℃, and after dehydration, nicotinic acid pyridoxine ester is generated; wherein, the amount of 97wt.% sulfuric acid added is 0.03% of the mass of pyridoxine phosphate.

[0011] The specific synthesis process of the polymerization reaction is as follows: pyridoxine nicotinic acid, liquid small molecule alcohol, and alkaline catalyst are added to the reactor. After nitrogen purging, the reactor is heated under vacuum and maintained at 80-85°C and 0.1-0.4 MPa. Epoxy alkane is added dropwise, and the reactor is allowed to mature for 1-2 hours after the addition is complete. The temperature is then increased to 105-110°C and the pressure is maintained at 0.1-0.4 MPa. Epoxy alkane is added dropwise again. After the feed is complete and the reaction pressure remains essentially constant, the pressure is increased to 0.2-0.3 MPa, and the reactor is allowed to mature for 2-3 hours. When dimethylamine is used as the alkaline catalyst, it needs to be introduced under vacuum after nitrogen purging.

[0012] Preferably, when liquid sorbitol is used as one of the raw materials, a dehydration step is added after the first ripening reaction. The specific steps are as follows: after ripening, the temperature is raised to 110°C, vacuum is drawn and nitrogen is bubbled for 1.5 hours, and the pressure is maintained at -0.09±-0.01MPa to remove water from the liquid sorbitol.

[0013] The post-processing is as follows: the system after polymerization reaction is kept at 105~110℃, then the pressure is maintained at -0.08~-0.1MPa, nitrogen is bubbled for 1~2 hours, and then filtered to obtain nicotinic acid modified pyridoxine phosphate polyether polyol.

[0014] The liquid small molecule alcohol is two or three of diethylene glycol, liquid sorbitol, and glycerol, wherein the liquid sorbitol has a water content of 30 wt.% and is purchased from Shandong Tianli Pharmaceutical Co., Ltd.

[0015] The epoxide is one or both of propylene oxide and ethylene oxide.

[0016] The sum of the amounts of nicotinic acid pyridoxine ester and liquid small molecule alcohol added is 42.5~45.5 wt. of the total amount of epoxide alkane added.

[0017] The amount of alkyl epoxide added in the first stage is 14.5 to 21.5 wt. of the total amount of alkyl epoxide added.

[0018] The alkaline catalyst is one or two of 2,4,6-tris(dimethylaminomethyl)phenol, N,N-dimethylcyclohexylamine, and dimethylamine.

[0019] A nicotinic acid-modified pyridoxine polyether polyol is prepared by the aforementioned method for preparing nicotinic acid-modified pyridoxine polyether polyol.

[0020] Specifically, the preparation method of the nicotinic acid-modified pyridoxine polyether polyol includes the following steps:

[0021] (1) Preparation of pyridoxine phosphate: Pyridoxine and 75wt.% phosphoric acid aqueous solution in a mass ratio of (1~1.68):1 were added to a reaction vessel, followed by the addition of solvent. The mixture was dissolved at room temperature, then heated and maintained at 107.5±2.5℃ and -0.09±0.01MPa. The mixture was then dehydrated under vacuum for 1.5h to obtain pyridoxine phosphate. The solvent was one or both of ethanol and chloroform.

[0022] (2) Preparation of nicotinic acid pyridoxine ester: Nicotinic acid and pyridoxine phosphate in a molar ratio of (1~1.8):1 were added to the reaction vessel, and then 97wt.% sulfuric acid (0.03% by mass of pyridoxine phosphate) was added. The esterification reaction was carried out at 200~220℃, and after bubbling dehydration for 1.5h, nicotinic acid pyridoxine ester was generated.

[0023] (3) Polymerization reaction: In a 2L high-pressure reactor equipped with a stirrer, metering device, heating and temperature control device, cooling device (including outer jacket and inner coil) and pressure sensor, add nicotinic acid pyridoxine ester, liquid small molecule alcohol and alkaline catalyst, purge the reactor with nitrogen to test for leaks, and purge with nitrogen under the condition that the reactor is well sealed. After the nitrogen purge is completed, raise the temperature to 82.5±2.5℃ and the pressure to 0.25±0.15MPa, add epoxide alkane dropwise, and mature for 1~2h after the dropwise addition is completed; continue to raise the temperature and control the temperature at 107℃. At 5±2.5℃ and 0.25±0.15MPa, epoxide alkane was added dropwise. After the feed was completed and the reaction pressure remained basically constant, the pressure was increased to 0.2~0.3MPa, and the mixture was allowed to mature for 2~3 hours. When dimethylamine was used as the alkaline catalyst, the alkaline catalyst needed to be purged with nitrogen and then vacuum-introduced. When liquid sorbitol was used as one of the raw materials, after the first stage of maturation reaction, the temperature was raised to 110℃, vacuum was applied, and nitrogen was bubbled for 1.5 hours while maintaining a pressure of -0.09±0.01MPa to remove water from the liquid sorbitol.

[0024] (4) Post-treatment: The matured polyether is kept at 107.5±2.5℃, and then the pressure is maintained at -0.09±0.01MPa. Nitrogen gas is bubbled for 1~2 hours, and then the material is discharged and filtered to obtain nicotinic acid modified pyridoxine phosphate polyether polyol.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] (1) The preparation method of nicotinic acid modified pyridoxine phosphate polyether polyol of the present invention converts pyridoxine into a derivative containing multiple alcohol hydroxyl groups, namely pyridoxine phosphate, by phosphorylation of pyridoxine, thereby increasing the number of hydroxyl groups, effectively improving the functionality, and further improving the reaction efficiency of the polymerization reaction; secondly, nicotinic acid pyridoxine ester is generated by esterification reaction between nicotinic acid and pyridoxine phosphate, and the presence of ester group and ether bond makes the nicotinic acid modified pyridoxine phosphate polyether polyol have good solubility, thereby improving the pentane miscibility of the product.

[0027] (2) The method for preparing nicotinic acid modified pyridoxine phosphate polyether polyol of the present invention uses ethanol and chloroform as solvents, which can be recycled and reused. Furthermore, nicotinic acid and pyridoxine are used as raw materials, which are environmentally friendly.

[0028] (3) The nicotinic acid modified pyridoxine phosphate polyether polyol prepared by the method of the present invention contains nitrogen, phosphorus, halogen and pyridine structure, which reduces the deformation between molecular chains. The product has excellent flame retardant properties, and has high activity and excellent compressive strength. Detailed Implementation

[0029] The present invention will be further described below with reference to embodiments and comparative examples. Unless otherwise specified, the raw materials used in the embodiments are all commercially available conventional raw materials; unless otherwise specified, the process methods used in the embodiments are conventional methods in the art.

[0030] Example 1

[0031] The preparation method of the nicotinic acid modified pyridoxine polyether polyol includes the following steps:

[0032] (1) Preparation of pyridoxine phosphate: 168g of pyridoxine and 130g of 75wt.% phosphoric acid aqueous solution were added to the reaction vessel, followed by the addition of ethanol and chloroform. The mixture was dissolved at room temperature, and then heated and kept at 107.5±2.5℃ and -0.09±0.01MPa. The mixture was then dehydrated by vacuum bubbling for 1.5h to obtain pyridoxine phosphate.

[0033] (2) Preparation of nicotinic acid pyridoxine ester: Nicotinic acid and pyridoxine phosphate in a molar ratio of 1.4:1 were added to the reaction vessel, and then 97wt.% sulfuric acid (0.03% by mass of pyridoxine phosphate) was added. The esterification reaction was carried out at 210℃, and after bubbling dehydration for 1.5h, nicotinic acid pyridoxine ester was generated.

[0034] (3) Polymerization reaction: In a 2L high-pressure reactor equipped with a stirrer, metering device, heating and temperature control device, cooling device (including outer jacket and inner coil) and pressure sensor, add 300g of liquid sorbitol, 50g of diethylene glycol, 200g of glycerol, 200g of pyridoxine nicotinic acid ester, and 7g of N,N-dimethylcyclohexylamine. Test the reactor for leaks by purging it with nitrogen gas. After ensuring the reactor is well-sealed, purge it with nitrogen. After purging, vacuum evacuate 11g of dimethylamine, then raise the temperature to 82.5±2℃. At 0.5℃ and 0.25±0.15MPa, 247g of ethylene oxide was added dropwise. After the addition was complete, the mixture was allowed to mature for 1 hour. Then, the temperature inside the reactor was raised to 110℃, and a vacuum was drawn while bubbling nitrogen to maintain a pressure of -0.09±0.01MPa for 1.5 hours to remove water from the liquid sorbitol. The temperature was controlled at 107.5±2.5℃ and the pressure at 0.25±0.15MPa, and 1410g of propylene oxide was added dropwise. After the feed was completed and the reaction pressure remained basically constant, the pressure was increased to 0.2MPa and the mixture was allowed to mature for 2 hours.

[0035] (4) Post-treatment: The matured polyether is kept at 107.5±2.5℃, and then the pressure is maintained at -0.09±0.01MPa. Nitrogen gas is bubbled. After bubbling for 1 hour, the material is discharged and filtered to obtain nicotinic acid modified pyridoxine phosphate polyether polyol. The hydroxyl value and viscosity (25℃) of this rigid foam polyether polyol were tested to be 415mgKOH / g and 4270MPa·s, respectively.

[0036] Example 2

[0037] The preparation method of the nicotinic acid modified pyridoxine polyether polyol includes the following steps:

[0038] (1) Preparation of pyridoxine phosphate: 168g of pyridoxine and 100g of 75wt.% phosphoric acid aqueous solution were added to the reaction vessel, followed by the addition of chloroform. The mixture was dissolved at room temperature, and then heated and kept at 107.5±2.5℃ and -0.09±0.01MPa. The mixture was then vacuum bubbled and dehydrated for 1.5h to obtain pyridoxine phosphate.

[0039] (2) Preparation of nicotinic acid pyridoxine ester: Nicotinic acid and pyridoxine phosphate in a molar ratio of 1:1 were added to the reaction vessel, and then 97wt.% sulfuric acid (0.03% by mass of pyridoxine phosphate) was added. The esterification reaction was carried out at 200℃, and after bubbling dehydration for 1.5h, nicotinic acid pyridoxine ester was generated.

[0040] (3) Polymerization reaction: In a 2L high-pressure reactor equipped with a stirrer, metering device, heating and temperature control device, cooling device (including outer jacket and inner coil) and pressure sensor, add 360g of liquid sorbitol, 100g of diethylene glycol and 130g of nicotinic acid pyridoxine ester. Purge the reactor with nitrogen to test for leaks. Under the condition that the reactor is well sealed, purge it with nitrogen. After the nitrogen purging is completed, vacuum pump in 7g of dimethylamine, and then raise the temperature to 82.5±2.5℃ and the pressure to 0.25±0.15MPa. Add 281g of propylene oxide dropwise, and after the addition is complete, allow it to mature for 1.5 hours. Then, raise the temperature inside the reactor to 110℃, evacuate the reactor, and bubble with nitrogen to maintain a pressure of -0.09±0.01MPa for 1.5 hours to remove water from the liquid sorbitol. After adding 6g of dimethylamine, control the temperature at 107.5±2.5℃ and the pressure at 0.25±0.15MPa, and continue to add 1041g of propylene oxide dropwise. After the feed is completed and the reaction pressure remains basically unchanged, pressurize to 0.25MPa and mature for 2.5 hours.

[0041] (4) Post-treatment: The matured polyether is kept at 107.5±2.5℃, and then the pressure is maintained at -0.09±0.01MPa. Nitrogen gas is bubbled for 1.5h, and then the material is discharged and filtered to obtain nicotinic acid modified pyridoxine phosphate polyether polyol. The hydroxyl value and viscosity (25℃) of this rigid foam polyether polyol were tested to be 374mgKOH / g and 6865MPa·s, respectively.

[0042] Example 3

[0043] The preparation method of the nicotinic acid modified pyridoxine polyether polyol includes the following steps:

[0044] (1) Preparation of pyridoxine phosphate: 168g of pyridoxine and 168g of 75wt.% phosphoric acid aqueous solution were added to the reaction vessel, followed by the addition of ethanol. The mixture was dissolved at room temperature, and then heated and kept at 107.5±2.5℃ and -0.09±0.01MPa. The mixture was then vacuum bubbled and dehydrated for 1.5h to obtain pyridoxine phosphate.

[0045] (2) Preparation of nicotinic acid pyridoxine ester: Nicotinic acid and pyridoxine phosphate in a molar ratio of 1.8:1 were added to the reaction vessel, and then 97wt.% sulfuric acid (0.03% by mass of pyridoxine phosphate) was added. The esterification reaction was carried out at 220℃, and after bubbling dehydration for 1.5h, nicotinic acid pyridoxine ester was generated.

[0046] (3) Polymerization reaction: In a 2L high-pressure reactor equipped with a stirrer, metering device, heating and temperature control device, cooling device (including outer jacket and inner coil) and pressure sensor, add 245g of diethylene glycol, 156g of glycerol, 152g of pyridoxine nicotinic acid, 6g of 2,4,6-tris(dimethylaminomethyl)phenol and 9g of N,N-dimethylcyclohexylamine. Nitrogen gas is introduced to test for leaks in the reactor. Under the condition that the reactor is well sealed, nitrogen gas is purged. After the nitrogen purging is completed, the vacuum temperature is raised to 82.5±2.5℃ and the pressure is 0.25±0.15MPa. 275g of ethylene oxide is added dropwise. After the addition is completed, it is matured for 2h. The temperature is raised to 107.5±2.5℃ and the pressure is 0.25±0.15MPa. 1016g of ethylene oxide is added dropwise. After the feeding is completed, when the reaction pressure is basically unchanged, the pressure is increased to 0.3MPa and matured for 3h.

[0047] (4) Post-treatment: The matured polyether was kept at 107.5±2.5℃, and then the pressure was maintained at -0.09±0.01MPa. Nitrogen was bubbled for 2 hours and then discharged and filtered to obtain nicotinic acid modified pyridoxine phosphate polyether polyol. The hydroxyl value and viscosity (25℃) of this rigid foam polyether polyol were tested to be 358mgKOH / g and 4546MPa·s, respectively.

[0048] Comparative Example 1

[0049] This comparative example is the same as Example 1, except that the preparation process of nicotinic acid pyridoxine ester is not included in this comparative example. That is, the polyether of this comparative example is prepared from step (3) of Example 1. Except for not containing nicotinic acid pyridoxine ester, the other steps, raw materials and raw material dosage are the same as in Example 1. The hydroxyl value and viscosity (25℃) of the polyether polyol finally obtained in this comparative example are 378 mg KOH / g and 6008 MPa·s.

[0050] Comparative Example 2

[0051] The preparation method of the nicotinic acid modified pyridoxine polyether polyol includes the following steps:

[0052] (1) Preparation of pyridoxine phosphate: 168g of pyridoxine and 130g of 75wt.% phosphoric acid aqueous solution were added to the reaction vessel, followed by the addition of ethanol and chloroform. The mixture was dissolved at room temperature, and then heated and kept at 107.5±2.5℃ and -0.09±0.01MPa. The mixture was then dehydrated by vacuum bubbling for 1.5h to obtain pyridoxine phosphate.

[0053] (2) Polymerization reaction: In a 2L high-pressure reactor equipped with a stirrer, metering device, heating and temperature control device, cooling device (including outer jacket and inner coil) and pressure sensor, add 150g of liquid sorbitol, 400g of diethylene glycol, 200g of glycerol, 350g of pyridoxine phosphate and 20g of 2,4,6-tris(dimethylaminomethyl)phenol. Nitrogen gas is introduced to test for leaks in the reactor. Under the condition that the reactor is well sealed, nitrogen gas is purged. Then the temperature is raised to 82.5±2.5℃ and the pressure is 0.25±0. At 15 MPa, 251 g of a mixture of ethylene oxide and propylene oxide was added dropwise. After the addition was complete, the mixture was allowed to mature for 1 hour. Then, the temperature inside the reactor was raised to 110℃, and a vacuum was drawn while bubbling nitrogen to maintain a pressure of -0.09±0.01 MPa for 1.5 hours to remove water from the liquid sorbitol. The temperature was controlled at 107.5±2.5℃ and the pressure at 0.25±0.15 MPa, and 2105 g of the mixture of ethylene oxide and propylene oxide was added dropwise. After the feeding was completed and the reaction pressure remained basically constant, the pressure was increased to 0.2 MPa and the mixture was allowed to mature for 2 hours.

[0054] (3) Post-treatment: The matured polyether was kept at 107.5±2.5℃, and then the pressure was maintained at -0.09±0.01MPa. Nitrogen was bubbled for 1 hour, and then the material was discharged and filtered to obtain nicotinic acid modified pyridoxine phosphate polyether polyol. The hydroxyl value and viscosity (25℃) of this rigid foam polyether polyol were tested to be 402mgKOH / g and 4658MPa·s, respectively.

[0055] Using the polyether polyols synthesized in Examples 1-3 and Comparative Examples 1-2 as raw materials, a composite material was prepared. The composite material consisted of component A and component B. Component A included the following raw materials in parts by weight: 100 parts polyether polyol, 1.5 parts water, 1 part PC-8, 2 parts M8815, and 14 parts cyclopentane. The catalyst PC-8 was a commercially available product from Wanhua Chemical Group Co., Ltd., and the silicone oil M8815 was a commercially available product from Jiangsu Meiside Chemical Co., Ltd. Component B was PM200, also a commercially available product from Wanhua Chemical Group Co., Ltd. Component A and component B were mixed evenly at a mass ratio of 1:1 and then foamed to obtain a rigid foam polyether polyol sample. The rigid foam polyether polyol samples corresponding to each example and comparative example were identical in terms of raw materials, raw material amounts, and steps, except for the different polyether polyols.

[0056] After mixing components A and B evenly, foaming was performed to verify the oxygen index, compressive strength, activity, and pentane miscibility of the foam.

[0057] Oxygen Index: The oxygen index of the examples and comparative examples was tested according to GB20286-2006 standard; Compressive Strength: The compressive strength of the examples and comparative examples was tested according to GB / T8813-2008 standard; Activity: The time taken from the start-up to the fiber drawing after the components A and B were fully mixed. The shorter the time, the higher the activity; Pentane Miscibility: The number of parts of n-pentane or cyclopentane that are completely miscible with 1 part of polyether polyol. The performance test results are shown in Table 1.

[0058] Table 1 Performance Test Table of Rigid Polyurethane Foam

[0059]

[0060] As shown in Table 1, through comparison of Examples 1-3 and Comparative Examples 1-2, the performance of the foam was significantly improved after the addition of pyridoxine nicotinic acid ester compared to the foam without pyridoxine nicotinic acid ester. This is because pyridoxine nicotinic acid ester contains nitrogen and phosphorus elements, which increases the oxygen index of the downstream foam, thereby improving its flame retardancy. Furthermore, both pyridoxine nicotinic acid ester and the blowing agent cyclopentane contain cyclic structures, and due to the principle of "like dissolves like," the miscibility of pentane is improved. Secondly, the presence of pyridine structures in pyridoxine nicotinic acid ester increases the compressive strength of the rigid polyurethane foam. Comparative Example 2 shows that when pyridoxine phosphate is used as the initiator to replace pyridoxine nicotinic acid ester, the resulting polyether polyol has poor miscibility with pentane due to the absence of ester groups in the system. Moreover, the lack of nicotinic acid modification leads to a low pyridine content and low product activity, resulting in a significant decrease in the compressive strength and flame retardancy of the rigid polyurethane foam.

[0061] As can be seen from the above embodiments, the nicotinic acid modified pyridoxine polyether polyol of the present invention, composed of nitrogen and phosphorus elements and cyclic structure, contains rigid chain groups in the polyether polyol macromolecular chain, thereby giving the product better compressive strength and flame retardancy.

Claims

1. A process for the preparation of a nicotinic acid-modified pyridoxamine polyether polyol, characterized in that, Nicotinic acid modified pyridoxyl phosphate polyether polyol is prepared by the following steps: pyridoxyl phosphate is prepared by reacting pyridoxamine with phosphoric acid aqueous solution; nicotinic acid pyridoxyl phosphate ester is prepared by esterification of nicotinic acid and pyridoxyl phosphate in the presence of a catalyst; and nicotinic acid modified pyridoxyl phosphate polyether polyol is prepared by polymerization of nicotinic acid pyridoxyl phosphate ester and liquid small molecule alcohol in the presence of an alkaline catalyst. The specific synthesis process of pyridoxyl phosphate is as follows: pyridoxamine and 75 wt.% phosphoric acid aqueous solution are added into a reaction kettle in a mass ratio of (1-1.68):1, followed by addition of a solvent, dissolution at room temperature, and dehydration under vacuum at a temperature of 105-110°C and a pressure of-0.08 to-0.1 MPa to obtain pyridoxyl phosphate. The specific synthesis process of nicotinic acid pyridoxyl phosphate ester is as follows: nicotinic acid and pyridoxyl phosphate are added into a reaction kettle in a molar ratio of (1-1.8):1, followed by addition of 97 wt.% sulfuric acid, and esterification at 200-220°C to obtain nicotinic acid pyridoxyl phosphate ester after dehydration. The liquid small molecule alcohol is two or three of diethylene glycol, liquid sorbitol and glycerol, and the alkylene oxide is one or both of propylene oxide and ethylene oxide.

2. The method of preparing nicotinic acid-modified pyridoxamine polyether polyol according to claim 1, characterized in that, The solvent is one or both of ethanol and chloroform.

3. The method for preparing nicotinic acid-modified pyridoxine polyether polyol according to claim 1, characterized in that, The specific synthesis process of the polymerization reaction is as follows: nicotinic acid pyridoxyl phosphate ester, liquid small molecule alcohol and alkaline catalyst are added into a reaction kettle, followed by nitrogen replacement, vacuum heating at a temperature of 80-85°C and a pressure of 0.1-0.4 MPa, dropwise addition of alkylene oxide, and aging for 1-2 h after completion of the dropwise addition; the temperature is further increased to 105-110°C and the pressure is further increased to 0.1-0.4 MPa, and the dropwise addition of alkylene oxide is continued, and after completion of the feeding, the pressure is increased to 0.2-0.3 MPa when the reaction pressure remains unchanged, and the system is aged for 2-3 h.

4. The method for preparing nicotinic acid-modified pyridoxine polyether polyol according to claim 1, characterized in that, The post-treatment process is as follows: the system after the polymerization reaction is kept at a temperature of 105-110°C, followed by nitrogen bubbling at a pressure of-0.08 to-0.1 MPa for 1-2 h, and filtration to obtain nicotinic acid modified pyridoxyl phosphate polyether polyol.

5. The method for preparing nicotinic acid-modified pyridoxine polyether polyol according to claim 1, characterized in that, The total amount of nicotinic acid pyridoxyl phosphate ester and liquid small molecule alcohol is 42.5-45.5 wt.% of the total amount of alkylene oxide.

6. The method for preparing nicotinic acid-modified pyridoxine polyether polyol according to claim 1, characterized in that, The alkaline catalyst is one or both of 2,4,6-tris(dimethylaminomethyl)phenol, N,N-dimethylcyclohexylamine and dimethylamine.

7. A nicotinic acid-modified pyridoxamine polyether polyol characterized by, The nicotinic acid modified pyridoxyl phosphate polyether polyol is prepared by the method of any one of claims 1-6.

Images